A string quintet is a musical composition for a standard string quartet (two violins, a viola, and a cello) supplemented by a fifth string instrument, usually a second viola (a so-called "viola quintet") or a second cello (a "cello quintet"), but occasionally a double bass. Wolfgang Amadeus Mozart, who favoured addition of a viola, is considered a pioneer of the form. Most famous of the cello quintets is Franz Schubert's Quintet in C major. Antonín Dvořák's Quintet Op. 77 uses a double bass, and Mozart's famous Eine kleine Nachtmusik may be performed with this instrumentation (the double bass being optional). Alternative additions include clarinet or piano (see Clarinet quintet, Piano quintet); and other closely related chamber music genres include the string quartet (much more common), the string trio, and the string sextet.
Many composers famous for their string quartets – such as Joseph Haydn (pioneer of the quartet genre), Béla Bartók, Paul Hindemith, and Dmitri Shostakovich – never composed a string quintet.
The term string quintet may refer to a group of five players that performs such works. It can also be applied to the standard five-part orchestral string section: first violins, second violins, violas, cellos, and double basses.
List of string quintet composers
- Leslie Bassett - double bass quintet (1957). (NY Public Library reference)
- Arnold Bax - one Cello Quintet in G major (1908), whose second movement was rescored by the composer for Viola Quintet and published as the Lyrical Interlude (1923); and one Viola Quintet (1933)
- Ludwig van Beethoven - Viola Quintet, Op. 29, sometimes called the Storm Quintet; a Fugue in D major for viola quintet, Op. 137; an arrangement of his Octet for Viola Quintet, Op. 4 (the original Octet was later published as Op.103); an arrangement of his Piano Trio Op. 1 No. 3 for Viola Quintet, Op. 104; an arrangement of his Violin Sonata in A, Op. 47, Kreutzer for Cello Quintet
- Wilhelm Berger - one Cello Quintet in E minor, Op. 75 (1911) 
- Luigi Boccherini - one hundred ten Cello Quintets, twelve original Viola Quintets, arrangements of all twelve of his Piano Quintets (Op.56 and Op.57) for Viola Quintet, and three Double Bass Quintets. The third movement Minuet of the Cello Quintet Op.11 No.5 is extremely well known.
- Alexander Borodin - one Cello Quintet in F minor
- Johannes Brahms - two Viola Quintets, Op. 88 and Op. 111; the Clarinet Quintet Op. 115 may be performed with a viola substituting for the clarinet
- Max Bruch - one Viola Quintet in A minor
- Anton Bruckner - one Viola Quintet in F major (1879); Intermezzo (=discarded trio section from Quintet)
- Luigi Cherubini - one Cello Quintet: Quintet in E minor (1837)
- Felix Otto Dessoff - one Cello Quintet, Op. 10
- Friedrich Dotzauer - Cello Quintet in D minor, Op. 134 (1835)
- Felix Draeseke - one Quintet in A for Two Violins, Viola, Violotta, and Cello (the Stelzner-Quintett; 1897) ; one Cello Quintet in F, Op. 77 (1901)
- Antonín Dvořák - two Viola Quintets, Op.1 in A minor and Op. 97 in E♭ (the American Quintet), and a Double Bass Quintet Op. 77 in G
- Victor Ewald - a Viola Quintet Op. 4 in A major 
- Friedrich Gernsheim - a Viola Quintet Op. 9 in D and a Cello Quintet Op. 89 in E♭
- Alexander Glazunov - one Cello Quintet in A, Op. 39
- Karl Goldmark - one Cello Quintet in A minor, Op. 9 (1862)
- Roy Harris - one Viola Quintet (1940)
- Vagn Holmboe - one String Bass Quintet, Op. 165/M.326 (1986)
- Heinrich Kaminski - one Viola Quintet in F♯ minor (two versions, first 1916) ()
- Nigel Keay - one Double Bass Quintet with Contralto, Tango Suite (2002) ()
- August Klughardt - Cello Quintet in G minor, Op. 62 (1902) 
- Franz Krommer - fifteen String Quintets
- Charles Martin Loeffler - one Violin Quintet (three violins, viola and cello)
- Frank Martin - Pavane couleur du temps (Colour of weather Pavane), 1920, 7', For cello quintet.
- Bohuslav Martinů - one Viola Quintet (1927)
- Felix Mendelssohn - two Viola Quintets: No. 1 in A major, Op. 18 (1826, revised 1832) and No. 2 in B-flat major, Op.87 (1845)
- Ernst Mielck - Viola Quintet in F major (1897)
- Darius Milhaud - one Double Bass Quintet Op. 316; one Viola Quintet Op. 325; one Cello Quintet Op. 350
- Wolfgang Amadeus Mozart - six Viola Quintets: K174, K516b, K515, K516, K593, K614
- Carl Nielsen - one Viola Quintet in G major (1888)
- George Onslow - thirty-four string quintets, mostly Cello Quintets.
- Hubert Parry - One Viola Quintet in E flat (1909, ) (Published by Chiltern Music in 1992)
- Einojuhani Rautavaara - One Cello Quintet Unknown Heavens (1997)
- Ottorino Respighi - one Cello Quintet in G minor (1901, incomplete)
- Josef Rheinberger - One Viola Quintet in A minor, Op. 82 (1874) ( Carus-Verlag)
- Ferdinand Ries - Seven Viola Quintets, op. 37 in C, Op. 68 in D minor, Op. 167 in A minor, Op. 171 in G, Op. 183 in E-flat, and two published without opus in A major and F minor (published in a series "Samtliche Streichquintette" edited by Jürgen Schmidt between 2003-5 for Accolade Musikverlag.)
- George Rochberg - Quintet for Two Violins, Viola and Two Cellos (1982)
- Franz Schubert - one Cello Quintet, Op. post. 163, D956, and a "Quintet-Overture" for Viola Quintet, D8
- Roger Sessions - one Viola Quintet (1958)
- Robert Simpson - one Viola Quintet (1987) and one Cello Quintet (1995)
- Ethel Smyth - one Cello Quintet in E major, Op. 1
- Louis Spohr - seven Viola Quintets
- Charles Villiers Stanford - Two Viola Quintets ()
- Johan Svendsen - one Viola Quintet in C, Op. 5 () (1868)
- Sergei Taneyev - one Cello Quintet in G, Op. 14, and one Viola Quintet in C, Op. 16
- Ferdinand Thieriot - several Cello Quintets. )
- Ralph Vaughan Williams - one Viola Quintet (the Phantasy Quintet - 1912)
- Felix Weingartner - one Viola Quintet, his Op. 40
- Alexander von Zemlinsky - one Viola Quintet (1894–1896): 2 movements are lost
- ^ Parlett, David. "Catalog of music by Bax (1930-1939)". Retrieved 2007-12-20.
- ^ a b "Merton Catalog". Retrieved 2007-10-23.
- ^ "Frank Martin Worklist". Retrieved 2007-10-23.
fr:Quintette à cordes it:Quintetto d'archi hu:Vonósötös no:Strykekvintett